A manual of laboratory and diagnostic tests

Chart 1.1 Grading Guidelines for Scientific Evidence Clear evidence from all appropriately A. Measure plasma glucose through an accredited lab to diagnose conducted trials or screen for diabetes Supportive evidence from well-conducted B. Draw fasting blood plasma specimens for glucose analysis studies or registries No published evidence; or only case, C. Self-monitoring of blood glucose may help to achieve better observational, or historical evidence control Expert consensus or clinical experience or D. Measure ketones in urine or blood to monitor and diagnose Internet polls diabetic ketoacidosis (DKA) (in home or clinic) As an integral part of their practice, clinicians have long supported patients and their significant others in meeting the demands and challenges incumbent in the simplest to the most complex diagnostic testing. This testing begins before birth and frequently continues after death. The clinician who provides diagnostic services must have basic requisite knowledge to plan patient care and an understanding of psychoneuroimmunology (effects of stress on health status), must make careful judgments, and must gather vital information about the patient and the testing process, to diagnose appropriately within the parameters of the clinician's professional standards ( Table 1.2 ; Chart 1.2). Table 1.2 Examples of Inappropriate Tests and Replacement Tests Inappropriate Replacement Prostatic acid phosphatase PSA or free PSA Ammonia AST, GGT Crossmatch (needed if blood is actually to be given) Type and screen Calcium Ionized calcium CBC Hemogram HCV antibody HCV RNA by PCR Iron Ferritin Lupus cell ANA Creatinine Urea CRP ESR PSA, prostate-specific antigen; AST, aspartate transaminase; GGT, gamma-glutamyltransferase; CBC, complete blood count; HCV, hepatitis C virus; PCP, polymerase chain reaction; ANA, antinuclear antibody; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate. Chart 1.2 Basics of Informed Care Manage testing environment using collaborative approach Communicate effectively and clearly Prepare the patient properly Follow standards Consider culture, gender, and age diversity Measure and evaluate outcomes; modify treatment as necessary Manage effective diagnostic services using team approach Interpret, treat, monitor, and counsel about abnormal test outcomes Maintain proper test records The diagnostic testing model incorporates three phases: pretest, intratest, and posttest ( Fig. 1.1). The clinical team actively interacts with the patient and his or her significant others throughout each phase. The following components are included with each laboratory or diagnostic test in this text: FIGURE 1.1 Model* for the role** of the clinical team in diagnostic care*** and services.**** Pretest Interventions: Intratest Interventions: Posttest Interventions: Test background information Normal (reference values) Explanation of test Indications for testing Actual description of procedures Specimen collection and transport Clinical implications of abnormal results Interfering factors Patient aftercare Clinical, education, and procedure alerts Special cautions Interpretation of test results Each phase of testing requires that a specific set of guidelines and standards be followed for accurate, optimal test results. Patient care standards and standards of professional practice are key points in developing a collaborative approach to patient care during diagnostic evaluation. Standards of care provide clinical guidelines and set minimum requirements for professional practice and patient care. They protect the public against less-than-quality care ( Table 1.3). Table 1.3 Standards for Diagnostic Evaluation Source of Standards for Diagnostic Service Standards for Diagnostic Testing Examples of Applied Standards for Diagnostic Testing Professional practice parameters of American Nurses Association (ANA), American Medical Association (AMA), American Society of Clinical Pathologists (ASCP), American College of Radiology, Centers for Disease Control and Prevention (CDC), JCAHO health care practice requirements Use a model as a framework for choosing the proper test or procedure and in the interpretation of test results. Use laboratory and diagnostic procedures for screening, differential diagnoses, follow-up, and case management. Test strategies include single tests or combinations/ panels of tests. Panels can be performed in parallel, series, or both. The guidelines of the major agencies, such as American Heart Order the correct test, appropriately collect Patients receive diagnostic services and transport specimens. Properly perform based on a documented assessment of Association, Cancer Society, and American Diabetes Association Individual agency and institution policies and procedures and quality-control criteria for specimen collection, procedure statement for monitoring the patient after an invasive procedure, and policy for universal witnessed consent situations. Statements on quality improvement standards. Use standards of professional practice and standards of patient care. Use policy for obtaining informed consent/witnessed consent. Use policies for unusual situations. tests in an accredited laboratory or diagnostic facility. Accurately report test results. Communicate and interpret test findings. Treat or monitor the disease and the course of therapy. Provide diagnosis as well as prognosis. Observe standard precautions (formerly known as universal precautions). Use latex allergy protocols and required methodology of specimen collection. Use standards and statements for monitoring patients who receive conscious sedation and analgesia. Vital signs are monitored and recorded at specific times before and after the procedure. Patients are monitored for bleeding and respiratory or neurovascular changes. Record data regarding outcomes when defined care criteria are implemented and practiced. Protocols to obtain appropriate consents are employed, and deviations from basic consent policies are documented and reported to the proper individual. need for diagnostic evaluation. Patients have the right to necessary information, benefits, or rights, to enable them to make choices and decisions that reflect their need or wish for diagnostic care. The clinician wears protective eyewear and gloves when handling all body fluids and employs proper handwashing before and after handling specimens and between patient contacts. Labeled biohazard bags are used for specimen transport. Vital signs are monitored and recorded at specific times before and after the procedure. Patients are monitored for bleeding and respiratory or neurovascular changes. Record data regarding outcomes when defined care criteria are implemented and practiced. Protocols to obtain appropriate consents are employed, and deviations from basic consent policies are documented and reported to the proper individual. State and federal government communicable disease reporting regulations; Centers for Disease Control and Prevention (CDC), U.S. Department of Health and Human Services, Agency for Health Care Policy and Research (AHCPR), and Clinical laboratory personnel and other health care providers follow regulations to control the spread of communicable diseases by reporting certain disease conditions, outbreaks, and unusual manifestations, morbidity, and mortality data. Findings from research studies The clinician reports laboratory evidence of certain disease classes (eg, sexually transmitted diseases, diphtheria, Lyme disease, symptomatic HIV infection; see list of reportable diseases). Personnel with hepatitis A may not handle food or care for patients, Clinical Laboratory Improvement Act provide health care policy makers with young children, or the elderly for a (CLIA) evidence-based guidelines for appropriate selection of tests and procedures. specific period of time. Federal government regulates shipment of diagnostic specimens. MR and CT are used to evaluate persistent low back pain according to AHCPR guidelines. U.S. Department of Transportation Alcohol testing is done in emergency rooms in special situations (eg, following a motor vehicle accident, homicide, or suicide, or an unconscious individual). Properly trained personnel perform blood, saliva, and breath alcohol testing and use required kits as referenced by federal law. Occupational Safety and Health Administration (OSHA) Workplace testing The clinician is properly trained, under mandated guidelines, to administer employee medical surveillance and respirator qualification and fit testing. JCAHO, Joint Commission on Accreditation of Healthcare Organizations; HIV, human immunodeficiency virus; MR, magnetic resonance; CT, computed tomography. If test results are inconclusive or negative and no definitive medical diagnosis can be established, other tests and procedures may be ordered. Thus, testing can become an involved and lengthy process (see Fig. 1.1). Understanding the basics of safe, effective, and informed care is important. These basics include assessing risk factors and modifying care accordingly, using a collaborative approach, following proper guidelines for procedures and specimen collection, and delivering appropriate care throughout the process. Providing reassurance and support to the patient and his or her significant others, intervening appropriately, and clearly documenting patient teaching, observations, and outcomes during the entire process are important (see Fig. 1.1). A risk assessment before testing identifies risk-prone patients and helps to prevent complications. The following factors increase a patient's risk for complications and may affect test outcomes: Age 70 years History of falls History of serious chronic illnesses History of allergies (eg, latex, contrast iodine, radiopharmaceuticals, and other medications) Infection or increased risk for infection (eg, human immunodeficiency virus [HIV], organ transplantation, chemotherapy, radiation therapy) Aggressive or antisocial behavior Seizure disorders Uncontrolled pain Gastric motility dysfunction Use of assistive devices for activities of daily living (ADLs) Unsteady gait, balance problems Neuromuscular conditions Weakness, fatigability Paresthesias Impaired judgment or illogical thinking Severe visual problems Hearing impairment Use of diuretics, sedatives, analgesics, or other prescription or over-the-counter (OTC) drugs Alcohol or illegal drug use or addiction